Bacteria such as methicillin-resistant staphylococcus aureus (MRSA) are a growing problem in hospitals and researchers are anxious to understand how they evolve.

Norwegian researchers said they had found little sign of such microbes in the feces of polar bears in the remote Arctic, suggesting the spread of resistance genes seen in the droppings of other animals may be due to human influence.

In contrast to the results from polar bears on the Svalbard archipelago, antibiotic resistance has been discovered in a range of animals including deer, foxes, pigs, dogs and cats that live close to humans.

Trine Glad of the University of Tromso said her team’s research, published on Thursday in the journal BMC Microbiology, was important evidence in the debate as to whether resistance occurs naturally or is caused by exposure to human antibiotics.

The rise of superbugs is prompting some drug companies to look again at antibiotics, a field that has been neglected in recent years. Both AstraZeneca and Sanofi-Aventis have signed new antibiotic research collaborations this week.\